.TH "QwtSystemClock" 3 "Fri Apr 15 2011" "Version 6.0.0" "Qwt User's Guide" \" -*- nroff -*-
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.SH NAME
QwtSystemClock \- 
.PP
\fBQwtSystemClock\fP provides high resolution clock time functions.  

.SH SYNOPSIS
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.PP
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\fC#include <qwt_system_clock.h>\fP
.SS "Public Member Functions"

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.RI "\fBQwtSystemClock\fP ()"
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.RI "virtual \fB~QwtSystemClock\fP ()"
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.RI "bool \fBisNull\fP () const "
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.RI "void \fBstart\fP ()"
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.RI "double \fBrestart\fP ()"
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.RI "double \fBelapsed\fP () const "
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.SS "Static Public Member Functions"

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.RI "static double \fBprecision\fP ()"
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.SH "Detailed Description"
.PP 
\fBQwtSystemClock\fP provides high resolution clock time functions. 

Sometimes the resolution offered by QTime ( millisecond ) is not accurate enough for implementing time measurements ( f.e. sampling ). \fBQwtSystemClock\fP offers a subset of the QTime functionality using higher resolution timers ( if possible ).
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Precision and time intervals are multiples of milliseconds (ms).
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\fBNote:\fP
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The implementation uses high-resolution performance counter on Windows, mach_absolute_time() on the Mac or POSIX timers on other systems. If none is available it falls back on QTimer. 
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.SH "Constructor & Destructor Documentation"
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.SS "QwtSystemClock::QwtSystemClock ()"
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Constructs a null clock object. 
.SS "QwtSystemClock::~QwtSystemClock ()\fC [virtual]\fP"
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Destructor. 
.SH "Member Function Documentation"
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.SS "double QwtSystemClock::elapsed () const"\fBReturns:\fP
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Number of milliseconds that have elapsed since the last time \fBstart()\fP or \fBrestart()\fP was called or 0.0 for null clocks. 
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.SS "bool QwtSystemClock::isNull () const"\fBReturns:\fP
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true if the clock has never been started. 
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.SS "double QwtSystemClock::precision ()\fC [static]\fP"\fBReturns:\fP
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Accuracy of the system clock in milliseconds. 
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.SS "double QwtSystemClock::restart ()"The start time to the current time and return the time, that is elapsed since the previous start time. 
.SS "void QwtSystemClock::start ()"Sets the start time to the current time. 

.SH "Author"
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